Digital over-the-air TV transmissions require a lot of broadcast spectrum - wide enough for each station to transmit four different TV signals at once. This wide broadcast spectrum can also make it easier for viewers to interact with their TV sets.More >>

If your local stations are transmitting digital signals and you're watching on cable - you aren't getting a digital picture. In order to receive digital TV pictures, you must have a digital TV set with a digital tuner.More >>

AP -- For digital television, the numbers sound impressive: two million TV sets sold in the last three years.

However, John Orlando with the National Association of Broadcasters says most of those sets aren't being used to receive digital over-the-air broadcast signals. He says only about a quarter of a million of them have digital tuners capable of receiving those transmissions. Orlando says the vast majority of these digital TV sets are being used for watching DVD's.

Digital television has been slow to catch on among consumers for several reasons: a lack of programming in the early days and expensive TV sets. Today, there's much more digital programming.